# EASB

Revision 0 2010-07-12 Approved under EASA DOA No. 21J.056 Page 1/11

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# EMERGENCY



# ALERT SERVICE BULLETIN

SUBJECT : ROTORS – MGB oil cooling fan

Checking play between a fan blade and the guide vane bearing housing

ATA: 65

Version(s) AIRCRAFT

CONCERNED NUMBER

Civil Militar y

SA330 05.96 J Ba, Ca, Ea, L, Jm, S1, Sm



### Revision No. Date of issue

Revision 0 2010-07-12



### Summary :

Check for a minimum play of 0.2 mm between a fan blade and the guide vane bearing housing

This check can be performed using a locally manufactured t ool. If the min. play is not complied with, replace the

two bearings of the fan rotor shaft.



### Compliance :

EUROCOPTER renders compliance with th is ALERT SERVICE BULLETIN mandatory. For the attention of

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### 1. PLANNING INFORMATION

1.A. EFFECTIVITY

1.A.1. Helicopters/installed equipment

On the Main Gearbox (MGB) fan assembly.

1.A.2. Non-installed equipment

Not applicable.



### 1.B. ASSOCIATED REQUIREMENTS

Not applicable.



### 1.C. REASON

EUROCOPTER has been informed of a new case of serious deterioration of the MGB oil cooling fan

assembly.

The fan rotor burst, due to its interference with the upper area of the guide vane bearing housing, and some

rotor blades have impacted the MGB compartment environment and caused puncture holes in the

transmission deck. However, the hydraulic pipes and f light controls located nearby were not affected by

impacts.

Such interference is due to the in ternal degradation of the fan bearings.

After a previous case, EUROCOPTER issued a Servic e Letter (LS) No. 1912-65-08 on August 12, 2008, to

inform of the modification of the fan maintenance cons isting in checking for contact between the fan rotor and

the guide vane bearing during the ALF inspection.

This additional maintenance set forth in this Se rvice Letter and introduced late in the documentation

(currently being issued), is cancel ed when the mandatory check of play, introduced by this ALERT SERVICE

BULLETIN, is carried out.

EUROCOPTER renders compliance with the instructi ons in this ALERT SERVICE BULLETIN mandatory to

enable the early discovery of the pot ential degradation of the fan rotor bea rings, by checking the play

between a fan blade and the guide vane bearing.



### 1.D. DESCRIPTION

- Check the play between a blade and the guide vane bearing housing:

. If the min. play is not complied with, re place the two bearings of the fan rotor shaft.

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### 1.E. COMPLIANCE

1.E.1. Compliance at the works

Not applicable.

1.E.2. Compliance in service

Helicopters/installed equipment :

Comply with paragraph 3. within 10 flighing hours fo llowing receipt of this ALERT SERVICE BULLETIN,

issued on the date indicated at the foot of the page.

Then,

Comply with paragraph 3. at inte rvals not exceeding 10 flying hours.

Non-installed equipment :

Not applicable.



### 1.F. APPROVAL

Approval of modifications :

Not applicable.

Approval of this document :

The technical information contained in this AL ERT SERVICE BULLETIN Revision 0 was approved on

12/07/2010 under the author ity of EASA Design Organisation Appr oval No. 21J.056 for civil version

helicopters subject to an Ai rworthiness Certificate.

The technical information contained in this AL ERT SERVICE BULLETIN Revision 0 was approved on

12/07/2010 under the registered letter Ref. 346621 DGA/ DT/CEP/ASA for French gov ernment helicopters.

The technical information contained in Revision 0 of this ALERT SERVICE BU LLETIN was approved on

12/07/2010 by the EUROCOPTER Ai rworthiness department for expor t military version helicopters.

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### 1.G. MANPOWER

Qualification :

1 Mechanical engineering technician.

Time for the operation :

- Approximately 2 hours for the first check of the pl ay (local manufacture of the tool included),

Then, approximately 10 minutes for all the other checks of the play.

- Approximately 6 hours to replace the bearings.



### 1.H. WEIGHT AND BALANCE

Not applicable.



### 1.I. EFFECT ON ELECTRICAL LOADS

Not applicable.



### 1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD

Not applicable.



### 1.K. REFERENCES

- Maintenance Manual (MDE) Work Card: 65.33.402.

- MAT 8582 Work Card: 321PA



### 1.L. OTHER DOCUMENTS AFFECTED

Not applicable.



### 1.M. INTERCHANGEABILITY OR MIXABILITY OF PARTS

Not applicable.

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### 2. MATERIAL INFORMATION

2.A. MATERIAL: PRICE - AVAILABILITY - PROCUREMENT

Price :

For any information concerning the cost of the kits and/or components for t he modifications, for the tools, or

for assistance, contact the EUROCOPTER Netw ork Sales and Customer Service Department.

Availability :

The kits, components or tools are delivered on the operator's order.

Procurement :

Order the required quantity (unless otherwise specified)

from

EUROCOPTER

Etablissement de Marignane

Direction Ventes et Relations Client

ECR

13725 MARIGNANE CEDEX

FRANCE



### NOTE 1

For ALERT SERVICE BULLETINS, order by:

Telex: HELICOP 410 969F.

Fax: +33 (0)4.42.85.99.96



### NOTE 2

On the purchase order, please specify the mode of transport, the

destination and the serial numbers of the helicopters to be odified.

The consumable materials listed in this ALERT SERVICE BULLETIN and in the referenced documents can

be ordered from:

INTERTURBINE AVIATION LOGISTICS,

Website: http://www.interturbine.com

Telephone : +49.41.91.809.300

AOG : +49.41.91.809.444



### 2.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT

EUROCOPTER remains at your disposal for any further information or support you may require to comply

with the instructions given in this ALERT SER VICE BULLETIN; please contact the EUROCOPTER

Customer Service Technical Support Department:

Phone: +33 (0)4.42.85.99.67

Fax: +33 (0)4.42.85.99.66

Email: DynComp.Technical-Support@eurocopter.com

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### 2.C. MATERIAL REQUIRED FOR EACH HELICOPTER/ENGINE/COMPONENT

Kits or components to be ordered for one helicopter or one assembly :

Description Qty Material P/N Item

Bearings 2 704A33651114 1

Tools :

Refer to the Work Cards referenced in this ALERT SERVICE BULLETIN.



### 2.D. MATERIAL TO BE RETURNED

Not applicable.

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### 3. ACCOMPLISHMENT INSTRUCTIONS

3.A. GENERAL

Refer to the general instructions given in MDE Work Card 65.00.301 or MAT 8582 Work Card 320A.



### 3.B. OPERATIONAL PROCEDURE

3.B.1. Preliminary steps

Open the sliding cowling.

3.B.2. Procedure

As per Figures 1 and 2

- Using a 0.2 mm (0.008 inches) feeler gauge attached to a locally manufactured rigid rod, check for a

minimum play of 0.2 mm between a fan rotor blade (a) and the upper section of the guide vane bearing

housing (b):

. Insert the tool through the fan grid (c) to check the play at the bottom of the guide vane bearing between

a blade (a) and the upper section of the guide vane bearing housing (b).



### NOTE

Play must be checked over the entire width of a fan blade.

In order to be inserted through the fan grid, the rigid rod equipped

with the feeler gauge, must have a maximum width of 12 mm, and

its length must be equal to 150 mm minimum.

Interpretation of the results:

a) If the feeler gauge can be inserted between the blade and the housing (play greater than or equal

to 0.2 mm):

- Leave as is.

- Return the helicopter to flight configurat ion in accordance with paragraph 3.B.3.

b) If the feeler gauge cannot be inserted between the blade and the housing (play less than 0.2 mm):

As per Figure 3

- Remove the two bearings (d) of the fan rotor shaft as per MDE Work Card 65.33.402 or MAT8582

Work Card 321PA.

- Install the two new bearings (1) as per MDE Wo rk Card 65.33.402 or MA T8582 Work Card 321PA.

- Return the helicopter to flight configurat ion in accordance with paragraph 3.B.3.

3.B.3. Final steps

- Close the sliding cowling.

- Resume flights.

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## DETAIL A

0.2 mm min. play over the

entire width of the blade



## a b

c

Figure 1 

### Area to be checked



# A c b b Area to be

checked

# EASB

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This document is available on the Internet: www.eurocopter.com/techpub Figure 2 

## c 0.2 mm min. play over the

entire width of the blade 

### Guide vane bearing housing

c



## a b

# EASB

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## d

1

d

1

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### 3.C. IDENTIFICATION

Identification of this document :

Record first compliance with this ALERT SERVICE BULLETIN in the log card of the fan assembly.



### 3.D. OPERATING AND MAINTENANCE INSTRUCTIONS

Not applicable.